This invention relates generally to heat pump systems and more particularly to a heat pump system for space heating and cooling as well as potable water heating.
Various heat pump systems have been proposed which not only have the capability of space heating and cooling but also have the capability of heating potable water. Many such systems simply use the condenser or a desuperheater to obtain the heat input for potable water heating. Such systems typically only heat the potable water when the heat pump system is operating for space heating or cooling. Other systems have been proposed in which the heat pump only serves to heat potable water and is not concerned with space heating or cooling. More recently, attempts have been made to combine these two types of systems to produce an integrated heating and cooling system with the capability of heating potable water.
These prior art attempts to produce an integrated system have resulted in an excessive number of control valves and other components. Also, these prior art systems usually have had certain limitations built therein as to how such systems could be used so that the flexibility of the system is limited. Further, these prior art systems frequently pumped refrigerant through coils not being used in the particular operating mode thereby increasing pumping pressure requirements, heat loss, and therefore operational and maintenance costs.